Vertical diffuser



Jul? 285 19.5.4' F. c. sCHAFFl-:R l-:TAL 3,1'4ZQ589- VERTICAL DIFFU'SERj I Filed May 15" 1962 I '5 Sheets-Sheet 1 INVENToRs .RobertI4/:McKenzie Francis C'. Schaffer ,Mil/MM BY L? ATTORNEYS VERTICALDIFFUSER Filed May 16, 1962 3 Sheeizs--Sheet 2 ATTORNEYS INVENTORSRobert W McKenzie Francis C.Sckaffer v BY 1j 351 35g Fi? 54 55] WOM'W*MM July 28,1964 Y F. c scHAFFl-:R ETAL 3,142,539

- vERf'rI'cAL nIFFusER Filed 'May 1e, 1962 V s sheets-sheet s INVENTORSRobert W McKenzie Francis C-Schaer 53h 55h 1:-1' E l ATTORNEYS UnitedStates Patent O 3,142,589 v VERTICAL DIFFUSER Francis C. Schaffer, 6755Merrydale Ave., and Robert W. McKenzie, 1836 Edinburgh Ave., both ofBaton Rouge, La.

Filed May 16, 1962, Ser. No. 195,176 9 Claims. (Cl. ITI-3) Thisinvention relates to improvements in apparatus for contacting solids orsemi-solids with fluids. More particularly, this invention relates toimproved apparatus for moving solids or semi-solids through or with aliquid or gas for such purposes as washing, leaching or diffusingextractable substances from the solids or semi-solids, adding substancesto or reacting substances chemically with the solids or semi-solids, ortransporting the solids or semi-solids in countercurrent or co-currentrelationship with the liquid or gas, and for other similar purposes.

Heretofore, spiral conveyors of conventional design having a singleshaft and helical flights of 180I degrees or more of rotation and withor without a limited number of interruptions into which stops orprojections are extended for breaking up or arresting spiral motion ofthe material being conveyed have proved adequate for conveying onlycertain types of materials. They have proved adequate in variousinstances for handling finely comminuted, granular or slipperymaterials, either in a dry state or wetted and conveyed through a liquidmedium.

None of the foregoing spiral conveying arrangements is adapted to conveyshredded, disintegrated or otherwise prepared short lengths of highlyfibrous and stringy materials in fluid suspension. Among this latterclass of materials, the reed or cane variety of plant life undoubtedlyrepresents substantially as difficult a material to convey in fiuidsuspension by means of a spiral conveyor as any other natural orartificial fibers. Other natural fibers, which are not quite asdifficult to convey spirally as materials in the class of sugar canefibers, are wood fibers or agglomerated masses of such fibers in theform of pulp derived from woody materials.

Recently, a spiral conveying device has been developed that has theability to convey such highly fibrous and wetted materials in a verticaldirection. As is more particularly described in U.S. Patent No.2,950,998, issued August 30, 1960, the device comprises a combination ofspirally arranged interrupted flights of particular dimension and pitchmounted on a single shaft for rotation and selectively spaced stationarydefiectors extending radially inwardly fom a cylindrical envelopesurrounding the fights. Although this device is effective in overcomingmany of the conveying problems noted above, it is mechanicallycomplicated and has a relatively narrow range of operationalflexibility. Furthermore, the device requires a plurality of openings inthe surrounding envelope `for the insertion of the spaced stationarydeflectors. These openings constitute a severe disadvantage in that theyprovide pockets and ledges that allow stagnation of material and thepossibility of bacteria formation and contamination.

The applicants have discovered that solids and semisolids, includingmany solids and semi-solids that could not heretofore be effectivelytransported, may be efhciently and continuously transported through aliquid or gas by a device having a unique arrangement of multiple,intermeshing, conveyor blades enclosed in a smooth-walled housing. Sincethe device is particularly effective in transporting solids andsemi-solids through fluids in a vertical direction, and since verticalcountercurrent contact with fiuids is generally the most efficient, thefollowing detailed description of the invention is presented withparticular reference to use of the device for effecting such movement.It is to be understood, however, that 3,142,589 Fatented July 28, 1964ice this description is for the purpose of illustration only, and thatmany other uses of the invention are contemplated as indicated above.

Accordingly, it is an object of the invention to provide an improvedform of apparatus for moving and/or diffusing particulate solid andsemi-solid materials in fluid media for the various purposes indicatedabove.

More specifically, and in accordance with what is generally the mostefiicient form of the apparatus, it is an object of the invention toprovide apparatus for moving particulate solid and semi-solid materialsin fiuid media in countercurrent or co-current relationship with thefiuid media; to maintain such solid and semi-solid materials in a highlydispersed state in the fluid media for intimate contact therewith; toprovide apparatus for carrying out such operations on a continuous basisas regards the flow of materials delivered to and discharged from theapparatus; and to provide such apparatus in a form capable of use in avariety of different ways with a variety of different solid, semi-solid,and fluid media.

The invention is characterized by a unique arrangement of multipleconveyor fiight sectors or blades mounted on each of a plurality ofparallel, rotatable shafts, surrounded by an outer housing having across-sectional configuration in planes normal to the aXes of the shaftsthat conforms closely to the envelope defined by the sets of rotatingblades.

Other objects and features of the invention and its attendant advantageswill be readily appreciated as the same become better understood byreference to the following detailed description when considered inconnection with the accompanying drawings wherein:

FIG. l is an elevational view of a vertical diffuser, which is thesubject of this invention, with portions of the outer housing cut awayto show one of the shafts, and showing the vertical diffuser in use asan integral part of a continuous liquid-solid diffusion system,according to one aspect of the invention.

FIG. 2 is a top plan view of the vertical diffuser of FIG. 1.

FIG. 3 is a sectional View taken on line 3 3 of FIG. l showing therelationship of flight sectors in a single fiight level.

FIG. 4 is an elevational view, partly in section, of the verticaldiffuser illustrated in FIG. l with the front housing removed along theline 4 4, looking in the direction of the arrows, and with portions ofthe screen removed for clarity.

FIG. 5 is a development of the vertical shafts of FIG. 4 showing therelationship of the flight sectors if the two front shafts of FIG. 4 arepositioned on either side and in line with the back two shafts. Forclarity, alternate pairs of fiignt sectors are shown to be axiallyrotated 90 from their true position.

FIG. 6 is a sectional view, similar to FIG. 3, showing a modification ofthis invention.

FIG. 7 is a sectional View, similar to FIG. 3, showing a furthermodification of this invention.

FIG. 8 is a development, similar to FIG. 5, showing a still furthermodification of the invention.

FIG. 9 is a sectional View similar to FIG. 3, showing a furthermodification of this invention.

FIG. 10 is a development of the vertical shafts of FIG. 9 showin g therelationship ofthe flight sectors.

FIG. ll is a sectional view similar to FIG. 3, showing a still furthermodification of this invention.

FIGURE l2 is a sectional View of the vertical shafts of FIG. 1l, theplane of the section being indicated by lthe line 12-12 in FIG. ll.

Referring now to the drawings in detail and panticul arly to FIGS. l and4, the illustnated apparatus comprises a smooth-walled housing 10 havinga cross-sectional configuration corresponding to an envelope about foursymmetrically arranged `and partially overlapping circles. This housingis provided with upper and lower flange portions 11 and 12,respectively. The lower end of the housing 1% is connected to a suitablepan structure which, in the embodiment illustrated, comprises a` casing13 having a crosssectional configuration that may be best described as aquadrate (square or nearly so). The casing 13 is secured to the lowerflange portion 12 of the housing, preferably by means of a flange 14 andbolts, not shown. A pan bottom 15 may suitably take the shape of adished member having a vertically extending wall portion conforming tothe configuration of the casing 13 and secured thereto by bolts, notshown, passing through a flange 16 of the pan bottom and a lower flange17 on the casing 13. The casing 13 and the vertically extending wallportion of the pan bottom 15 have somewhat greater cross-sectionaldimensions, measured in planes normal to the axes of the shafts, thanthe corresponding cross-sectional dimensions of the housing 10, as bestshown in FIGS. 3 and 4.

Within the casing 13, and substantially as an extension of the housing10, a hollow cup-shaped screen shell 1S is provided. A verticallyextending wall portion 19 of the screen shell rises above a bottomportion 2t) thereof and conforms to the cross-sectional shape of thehousing 1t). The bottom portion 20 of the screen shell 18 extendslaterally to engage and conform to the wall of the casing 13. The bottomportion 20 is secured or welded to the casing 13 about its circumferenceland is similarly secured or welded to the base of the wall portion 19of the screen shell.

As is shown in FIGS. 3 and 4, an annular space cr chamber is thusprovided between the casing 13 `and the wall portion 19 of the screenshell 18, and this annular chamber is in substantially opencommunication (through the outer margin of the bottom portion 20 of thescreen shell) with a lower chamber between the bottom portion 2t) of thescreen shell and the pan bottom 15. Fluids at the bottom of the housing10 may flow through the screen shell into these chambers for withdrawalin a manner to be hereinafter set forth. The number and size of theholes in the screen shell provided to permit such flow will be governed,of course, by the characteristics of the particular solid, semi-solid,fibrous or agglomerated materials being conveyed. It will be appreciatedthat the type and thickness of the material used for the screening willalso depend on the specific application, and if extremely thin gaugescreening material is used, additional backing or reinforcing membersbetween the screen and the casing 13 may be required. It will also beappreciated that the entire screen surfaces 19 and 20 may be provided inthe form of a unitary and replaceable basket.

A top cover plate 22 is provided at the upper portion of the housing 10and is secured to the flange 11 by welding or bolts, not shown. Aplurality of shafts 23, 24, 25, and 26, extend through the cover plate22, and each is journalled for rotation within and vparallel to thesides of housing 10 by a thrust bearing 27 and collar 28 located on thecover plate 22. The lower ends of shafts 23-26 are reduced, and each isreceived by a suitable guide bearing 29 axially aligned with thecooperating thrust bearing 27. The guide bearing 29 is supported bymeans of a spider arrangement 30, which is, in turn, affixed to the panbottom 15. The shafts 23-26 are respectively rotated by a correspondingplurality of motors 31, each acting through a suitable reduction gearbox 32.

About the shafts 23-26, flight sectors 33 are affixed in any suitablemanner, such as by welding, in la stepped intermeshing arrangement to behereinafter set forth. The individual flight sectors have leading andtrailing edges 313 and 35, respectively. The edge that leads, of course,is dependent upon the direction of rotation of the flight sectors 33,and this direction is shown in the drawings to be clockwise (see thedirectional arrows in FIG. 3).

The flight sectors 33 may have either a flat or helical surface. In thecase of helically formed flight sectors, the pitch of the flightsectors, that is, the angle of the outer periphery of the flights to thehorizontal, may vary from zero degrees to about ninety degrees. Foreffective conveying, of course, the flight sectors would not be pitchedat precisely zero degrees or precisely degrees but would define an anglewithin, but not including these limits. For a flight sector having aflat surface, the pitch angle would be the angle defined by the planewithin which the flight sector lies with respect to the horizontal, and,for effective conveying, would be within the operable range as wasexplained above. In order to move solids or semi-solids effectivelyupwardly through the housing 10, a major portion of the leading edge ofthe flight sector 33 would be lower than the trailing edge.

Actually the pitch angle of a given flight sector is not the onlydetermining factor as to whether a given material may be effectivelymoved through the apparatus. More significant is the vertical distancebetween the leading and trailing edges of the flight sectors 33,measured at any given point along the leading or trailing edges. For adesired vertical distance at the outer periphery of a flight sector 33,the flight pitch angle would be less for a large diameter apparatus thanfor a smaller diameter apparatus.

If the apparatus is to be used to process fibrous plant materials suchas sugar cane cut into small discs the diameter of the cane and fromabout 1/16 to about one inch in length (or shredded to produce canepieces in longer lengths but of a diameter less than that of theoriginal cane), a vertical distance of between zero and l2 inchesbetween the leading and trailing edges of each flight sector constitutesa practical range for a unit of moderate diameter, say 8 to 12 feet. Ofcourse, for effective lifting and conveying, the distance would not beprecisely zero, but would be a finite value up to and including l2inches. Thus, the vertical distance between the leading and trailingedges of a flight sector may be 12 inches measured at its periphery andmay decrease and approach zero for inwardly spaced points concentricallylocated along the leading and trailing edges. The vertical distancebetween concentrically located inwardly spaced points along the leadingand trailing edges need not necessarily decrease from the outerperiphery but may remain constant. In such a case, the pitch angle ofthe outer periphery of a flight sector would be less than that of aninner periphery 36.

In the embodiment illustrated in FIGS. 1-5 and 8, each flight sector 33is a ninety degree circular segment, the inner periphery 36 of which isarcuate and has a radius complementary to the radius of its associatedshaft. Also, in the embodiment illustrated in FIGS. 1-5 and 8, whereinthe housing 10 has four vertical shafts 2326, each 90 degree flightsector 33 is attached to its shaft in diametrical alignment with acorresponding, opposite flight sector. Thus, as is illustrated in FIG.3, a flight sector 33a is diametrically aligned with a flight sector 33band has its leading edge 34 spaced ninety degrees from the trailing edge35 of the opposite flight sector 33b. Upon rotation of a vertical shaft,each pair of flight sectors traverses a common annular flight path zone.

This invention, however, is not limited to the ninety degree flightsectors illustrated. A vertical diffuser according to this invention mayhave, in `one annular flight path zone, any number of flight sectorshaving any desired sectorial area. Thus, for example, a circular flightpath area may have three 60 degree flights, four 45 degree flights, ortwo 77 degree flights. An annular flight path zone may contain only one.flight sector that defines an arc of more than zero and less than 360degrees, or that forms a helical segment of more than 360 degrees.

Referring particularly to FIG. 4, shafts 23-26 are alike and only oneneed be described. Referring to the shaft 23, it is provided with aplurality of pairs of diametrically aligned flight sectors 33. Alternatepairs of the flight but is spaced slightly therefrom for clearance.

sectors 33 are staggered so that the leading edge 34 of a flight sector33C is longitudinally spaced from and is directly below and in verticalalignment with the trailing edge 35 of a flight sector 33d. Similarlythe trailing edge 35 of the flight sector 33C is longitudinally spacedfrom and is directly below and in vertical alignment with the leadingedge 34 of a flight sector 33e which is in diametrical alignment withthe flight sector 33d.

The diffuser may comprise one or more conveying sets of shafts and theirflight sectors. In accordance with this invention, flight sectors andthe shafts with which they are associated constitute one or moreconveying sets. For purposes of this invention a set is used todesignate at least two vertically extending parallel shafts, each shafthaving flight sectors which, upon rotation, define annular flight pathzones that overlap and intermesh with the flight path zones defined bythe flight sectors of each other shaft in the set. Since there is anoverlapping and intermeshing of flight sectors within a set, it isimperative that the annular flight path zones on one shaft do notproject vertically into neighboring flight path zones on another shaft.It is also imperative that the flight sectors be arranged on the shaftsso that the solids and semi-solids may be effectively conveyed from thebottom to the top of the apparatus. The flight zones in each set aretherefore arranged in a stepped spiral manner.

In the embodiments shown in FIGURES l through 8, all of the flight pathzones defined by the flight sectors are overlapping and intermeshingand, according to the definition previously set forth, constitute oneconveying set. As can be seen more clearly in FIG. 5, the singleconveying set illustrated therein includes a diametrically alignedflight pair consisting of the flight sectors 33C and 33jL on the shaft23, and this flight pair is spaced from the flight pair consisting ofthe flight sectors 33d and 33e by a distance equal to the sum of thethickness of the flight path zones defined by the flight pairsconsisting of the flight sectors 33g and 33h on the shaft 24, the flightsectors 331' and 33j on the shaft 25, and the flight sectors 33k and 33!on the shaft 26. Thus, it can be seen that in a single conveying set thedistance between a pair of adjacent, axially aligned flight path zones(i.e., between the spaced flight path Zones on any given shaft) is equalto the total number of shafts in a set, minus one, times the verticalthickness of the zones therebetween. Added to this distance, of course,is the necessary clearance space provided between each of theoverlapping flight pairs. Similar longitudinal spaces are providedbetween all the other adjacent flight pairs on each of the shafts 23-26.Thus, when the shafts 23-26 are positioned as is shown in FIGS. 1 4,each flight pair constitutes a step in a spiral extending from thebottom to the top of housing 10.

The housing is a smooth-walled housing free from projections andopenings as is shown particularly in FIG. 3. The housing l0 conformsclosely to the outer envelope of all of the flight path zones defined bythe flight sectors,

This arrangement allows a continuous uninterrupted flow of solids and/orsemi-solids through the apparatus and prevents stagnation andcontamination of materials. As was stated above, the Vertical wallportion 19 of the screen 18 is a continuation of the housing 1t), and,therefore, has a cross-sectional configuration similarly conforming tothe outer envelope of all of the flight path zones.

Near the top of the housing 10 and above the uppermost of the flightsectors 33, there is provided a discharge opening 37. This openingmay'be of any convenient Size and provides a discharge exit for thespent, solid material after it has been conveyed upwardly through theentire length of the housing 10 in contact with the liquid or gaseousmedium therein. The discharge of solid material from the top of thehousing can be eected by means of a conventional rotary sweep havingfrom two to four sweep arms 38 and operating from a sweep shaft 39,mounted for rotation externally of the housing 10 and parallel to theaxes of the shafts 23-26 or other suitable means. The sweep arms 3S arepreferably curved concave to the direction of rotation, and are inlength adequate to extend from the sweep shaft 39 into the housing 10through the opening 37 to closely adjacent the shaft 25. The sweep arms38 are driven by a motor 40 connected through an appropriate reducer 41,to the sweep shaft 39. A collecting trough 42 is secured to the upperhousing 10 at the discharge opening 37 to receive material from thesweep arms 38. Although a conventional rotary sweep conveyor of the typeset forth herein is preferred in the disclosed embodiment, otherdischarge devices, such as a drag conveyor or a screw conveyor, may beemployed.

The lower portion of the pan bottom 15 is provided with an outletorifice 44 which is in fluid communicaiton with a T-joint 43 through anoutlet pipe 45. A conduit 46 extends from one branch of the T-joint 43and is provided with a suitable valve means 47. The conduit 46 isintended to be connected to a line for carrying off the heavier liquidmedium, which will settle to the bottom of the pan 15, to a processingor reprocessing destination. The other branch of the T-joint 43 isprovided with a conduit 48 having a suitable Valve means 49 providedtherein. The conduit 48 is provided in the event that it is desired towithdraw from the bottom some of the heavier liquid medium which has sogravitated for recycling through the vertical diffuser.

The conduit 48 leads to an optional heat exchanger 50 of standardconstruction and a conduit 51 is provided between the heat exchanger 50and a mixing hopper 52 provided with any conventional, power operated,stirring apparatus or the like, not shown. The heat exchanger 50 servesto heat the recycled liquid before re-introduction into the verticaldiffuser, and the mixing hopper 52 serves to collect and mix both theheated liquid to be recycled and raw, solid materials to be introducedinto the vertical diffuser. A conduit 53 leads from the bottom of themixing hopper 52 to a conventional rotary pump 54 which is preferably ofthe open impeller or non-clogging type or other suitable means ofinjection. Solids and recycled liquid are introduced into the verticaldiffuser through a conduit 55 which extends from the pump 54 through thecylindrical casing 13 and terminates in an aperture in the verticallyextending wall portion 19 of the screen 18. The solids and recycledliquid are immediately subjected to the conveying action of the flightsectors 33 which will hereinafter be explained.

A countercurrent flow of liquid is established by providing a liquidinlet conduit 56 near the top of the housing 10. It is desirable tomaintain a liquid level in the housing 10 which is slightly below thedischarge opening 37 to prevent liquid from flowing out the dischargeopening 37, but to permit the sweep arms 38 to skim off the spent solidsfrom the surface of the liquid. This may be accomplished by eithermanually adjusting valves 47 and 49 to permit a liquid flow therethroughcorresponding to the flow of liquid through inlet conduit 56, or byproviding a suitable liquid level control device, not shown, at thedesired liquid level for actuating inlet or outlet valves toautomatically control the flow of liquid into or out of the verticaldiffuser as required to maintain a constant level therein.

A more complete understanding of the invention will be had from adescription of its operation. The fibrous or agglomerated solid materialis first comminuted and preferably suspended in a portion of the liquidmedium withdrawn from the vertical diffuser through conduit 48 providedfor that purpose. This is accomplished in the mixing hopper 52. In thecase of sugar cane, a suitable solvent, preferably hot water, isintroduced into the housing through the inlet conduit 56. A portion ofthe sugarenriched water is drawn from the bottom of the verticaldiffuser through the conduit 48, reheated by the heat exchanger 50, andis admitted to the mixing hopper 52. Raw sugar cane, cut into smalldiscs the diameter of the cane and from 1/16 to one inch in length, isadded to the mixing hopper 52 where it is comminuted and suspended in aportion of enriched liquid withdrawn from the vertical diffuser as wasexplained above. The heated suspension of cane chips and juice is drawnfrom the mixing hopper 52 by the pump 54 and fed into the screen shell18 near the bottom thereof through the conduit 55. At the same time, thesolvent is continuously introduced into the top of the housing 10through conduit 56 as was stated above. The rate of introduction of thesuspended solid material to be conveyed through the housing 1t) and theintroduction of solvent at the top of the housing 10 is correlated andmay be automatically controlled by automatic weighing and controllingapparatus, not shown, available commercially for such purposes.

Because of variations in the movement of particles of solid materialdistributed over the horizontal cross-section of the housing 1G at anygiven elevation or level, there is no one characteristic path thatparticles of solid material follow during their journey from the bottomto the top of the vertical diffuser. In general, however, suspendedsolid material introduced through conduit 55 would be picked up from thebottom portion 20 of the screen 1S by the leading edges 34 of the flightsectors 33e and 33j and rotated in a clockwise direction. During thisrotation the solid material tends to move toward the trailing edges 35of the flight sectors 33e and 33j on the shaft 23 and be raised so as tobe picked up by the leading edges of the flight sectors 33g and 33h onthe shaft 24. In the same manner, the solid material is conveyed toflight sectors 33 and 33j on the shaft 25 and from these flight sectorsto flight sectors 33k and 331 n the shaft 26. The solid material, in thesame manner, is conveyed back to the flight sectors of the shaft 23,where it is picked up by the flight sectors 33d and 33e thereof. Thecycle is repeated by the higher flight sectors until the solid materialreaches the upper surface of the fluid. In this manner the suspendedsolid material is moved upwardly in a slowly ascending, stepped,generally spiral pattern through the vertical diffuser. At the sametime, the fluid in the vertical diffuser is following a tortuous,generally downward path.

It will be apparent that, depending upon the purpose for which the solidmaterial is being conveyed through the fluid medium, it will beprogressively washed, leached, or diffused from the cells of the solidmaterial. In the case of sugar cane chips, sucrose is probablysubstantially diffused from the cells by dialysis, and liquid mediumwill be infused into the cells by osmosis. The material so washed,leached or diffused from the solid material being conveyed may dissolvein the fluid medium, if the latter is chosen for its solvent propertieswith respect to the particular solid material being conveyed, and thedensity of the fluid medium thereby increases. The more dense fluidmedium accumulates at the lower end of the vertical diffuser for threereasons. The first reason is that the newly introduced light fluid, asits weight increases by its gradually increasing content of dissolvedmaterial, gravitates downwardly. The second reason is that fresh solidmaterial is being introduced at the bottom of the vertical diffuser andgreater soluble amounts of the solid material are immediately washed,leached or diffused in the area of initial contact with the fluidmedium. A third reason in the operation suggested herein is, of course,that the fresh material is initially suspended in a recycled portion ofthe already concentrated fluid medium from the pan portion of thevertical diffuser.

As the shafts slowly rotate in the direction indicated and suspendedsolid, fibrous, or agglomerated materials are conveyed upward throughthe fluid medium, the material is placed continuously in contact withfluid of less and less concentration, whereby, because of the lawsgoverning dilution or the laws governing the interfacing Cil u of fluidsof different densities, the dynamic forces tend to carry the materialsof higher concentration into the fluid medium of less concentration sothat increasingly greater total percentages of materials have beenwashed, leached, or diffused from the solid material as it moves towardthe upper end of the vertical diffuser where the fresh solvent medium isbeing introduced.

The height of the vertical diffuser and speeds of rotation of the shaftsfor any given diameter unit determine the quantity of solid materialthat can be conveyed through the vertical diffuser per unit time.Although the vertical diffuser is initially designed in height for aspecific solid material or group of solid materials to be treatedtherein, a great degree of latitude may be had for different solidmaterials in this type of device in that the contacting time may bevaried up or down by the adjustment, within limits, of the speeds of theshafts. The relationship is, of course, direct as will be apparent, sothat the through-put tends to vary directly with the speed of rotationof the shafts, and the contacting time tends to vary inversely with thespeed of rotation of the shafts, although it will be understood thatsuch variations are not necessarily straight line relationships.

The solid materials conveyed through the diffuser ultimately reach theuppermost flights of a shaft, which in the embodiment illustrated inFIGS. l-5, would be the uppermost flight pair affixed to the shaft 25.At this time, due to the correlation of the height of the verticaldiffuser, the liquid media therein, and the speed of rotation of theshafts, the solid materials are satisfactorily washed, leached, ordiffused as the specific case may be, and are ejected from the verticaldiffuser through the discharge opening 37 by the sweep arms 38.

Preferably the shafts operate at the same speed and in the samedirection. However, if dead spots occur in the fluid-solid suspensionbecause of equal pressures induced by equal speeds, the speeds ofdifferent shafts may be varied to insure continuous movement anddispersion of the solids. In some instances, moreover, it may bedesirable to drive one shaft at a much faster speed than the others.This shaft would act as a stirrer while the remaining shafts wouldeffect the countercurrent motion of the solids as explained above.

According to another aspect of this invention, a plurality ofintermediate flight sectors or blades 57 may be affixed to each shaftmidway between each flight pair. Thus, in FIG. 8, the shaft and flightsector arrangement is identical to that shown in FIG. 5, except that oneach shaft an intermediate flight sector 57 is affixed to the shaftmidway between the flight pairs. If a diametrically aligned pair ofintermediate flight sectors 57 are affixed to a shaft 58 midway betweentwo pairs of flight sectors 33m-3311 and 33o-33p, however, they would,upon rotation, define intermediate flight path zones that would lie inthe same plane as the flight path zone defined by a pair of flightsectors 33g and 331' on shaft 59. This is true of all the intermediateflight sectors 57. It is necessary, therefore, to reduce the radial sizeof all the intermediate flight sectors 57 so that they will clear thecoplanar flight sector. These intermediate flight sectors are intendedprimarily to prevent dead spots between flight sectors on the sameshaft, although they may be designed to effect some lifting andconveying action.

The invention is not limited to the preferred embodiment illustrated inFIGS. 1-5 and 8 and described above where the vertical diffuser isprovided with four shafts. FIG. 6 illustrates a single conveying set,two-shaft diffuser having a plurality of 45 degree flight sectors 33s.The shafts 60 and 61 are parallel and are vertically extending. Similarto the preferred embodiment, a smoothwalled housing 10a conforms closelyto the outer envelope of all of the flight path zones defined by theflight sectors 33s, but is spaced therefrom for clearance. The flightsectors 33s are intermeshing and convey solids in 9 a stepped spiralpath similarly to the preferred embodiment.

FIG. 7 illustrates a cross-section of a single conveying set, verticaldiffuser having three parallel and vertically extending shafts 62, 63,and 64 with spaced, intermeshing Hight sectors 33t. A smooth-walledhousing 10b conforms closely to the outer envelope of all of the Hightpath zones defined by the Hight sectors 33t, but is spaced therefrom forclearance.

FIGURES 9 through 12 illustrate vertical diffusers having multipleconveying sets according to a further aspect of this invention. FIG. 9illustrates a cross-section of a vertical diffuser having seven paralleland vertically extending shafts 65, 66, 67, 68, 69, '70, and 71. Mountedon these shafts are spaced intermeshing, Hight sectors 133a, 13312,133e, 133d, 133e, 133i, and 133g. These Hight sectors are shown to be ofvarying sectorial areas to illustrate that the Hight sectors in a singleset or multiple set vertical diffuser need not be identical.

The seven shaft vertical diffuser of FIG. 9 comprises six conveying setswhich are composed of the radially aligned Hight sectors of the shafts65, 66, and 67; 65, 67, and 68; 65, 68, and 69; 65, 69, and 70; 65, 70,and 71; and 65, 71, and 66, respectively. In a single conveying set, thedistance between adjacent, axially aligned Hight path zones is equal tothe total number of shafts in that set, minus one, times the verticalthickness of the Hight path zones. Thus, as can be seen in FIG. 10, inthe conveying set comprising the shafts 65, 66, and 67, the distancebetween the axially aligned Hight path zones deHned by the flightsectors 133:1 on the shaft 65 is equal to the number of shafts in thatset, minus one, times the vertical thickness of the zones. Added to thisdistance, of course, is the necessary clearance space provided betweeneach of the overlapping Hight sectors.

FIG. 1l illustrates a cross-section of a vertical diffuser having threeparallel and vertically extending shafts 72, 73, and 74. Mounted onthese shafts are spaced intermeshing, Hight sectors 133k. The threeshaft vertical diffuser of FIG. 11 comprises two conveying sets, asdistinguished from the one-set, three-shaft, vertical diffuser of FIG.7. The two conveying sets are defined by shafts 72 and 73, and 72 and74, respectively. In a single conveying set in FIG. l2, the distancebetween the axially aligned Hight path zones defined by the Hightsectors 133k is determined by the previously explained formula.

Although the invention has been described with particular reference tothe use of the apparatus for effecting vertical countercurrent motionbetween solids and Huids, the utility of the apparatus is not limitedthereto. The apparatus may be employed to effect chemical reactionsbetween solid and Huid substances, to desiccate wet solids or to wet drysolids. Co-current How for any of the above purposes may be carried outby introducing both the Huid and solid substances, under pressure, atthe lower end of the housing, and providing a suitable Huid and soliddischarge aperture near the top of the housing. The apparatus, in someinstances, need not be vertical and may even be horizontally disposed,although, as was explained above, a vertically disposed apparatus isgenerally most eHicient for countercurrent, Huid-solid contact.

The form of the invention described herein is intended to beillustrative and the invention should not be considered as limitedexcept as defined in the following claims.

What is claimed is:

l. Apparatus for moving solid and semi-solid materials in fluid media,comprising at least two vertically extending parallel shafts journalledfor axial rotation, a multiplicity of radially extending flight sectors,each having a leading and trailing edge, mounted on each of said shaftsand, upon rotation of said shafts, defining annular Hight path zones,said flight path zones of each shaft overlapping and intermeshing withthe flight path zones defined by the Hight sectors of at least one othershaft and each flight path zone being axially spaced from adjacentflight path zones on the same shaft, each flight path zone beingoccupied only by the flight sectors of a single shaft, and a verticallyextending smooth-walled housing enclosing said shafts and said flightsectors, said housing conforming closely to the outer envelope of all ofsaid flight path zones.

2. Apparatus for moving solid and semi-solid materials in fluid media,comprising at least two vertically extending parallel shafts journalledfor axial rotation, a multiplicity of radially extending Hight sectors,each having a leading and trailing edge, mounted on each of said shaftsand, upon rotation of said shafts, defining annular flight path zones,said flight path zones of each shaft overlapping and intermeshing withthe Hight path zones defined by the flight sectors of at least one othershaft and each flight path zone being occupied only by the Hight sectorsof a single shaft and being axially spaced from an adjacent flight pathzone on the same shaft a distance corresponding to the total thicknessof the overlapped flight path zones therebetween, and a verticallyextending smooth-walled housing enclosing said shafts and said flightsectors, said housing conforming closely to the outer envelope of all ofsaid flight path zones.

3. Apparatus for moving solid and semi-solid materials in fluid media,comprising at least two vertically extending parallel shafts journalledfor axial rotation, a multiplicity of radially extending flight sectors,each having a leading and trailing edge, mounted on each of said shaftsand, upon rotation of said shafts, defining annular flight path zones,said flight path zones of each shaft overlapping the flight path zonesdefined by the flight sectors of each other shaft and each flight pathzone being occupied only by the flight sectors of a single shaft andbeing axially spaced from an adjacent flight path zone on the same shafta distance corresponding to the total number of shafts, minus one, timesthe vertical thickness of said flight path Zones therebetween, and avertically extending smooth-walled housing enclosing said shafts andsaid flight sectors, said housing conforming closely to the otherenvelope of all of said flight path zones.

4. Apparatus for moving solid and semi-solid materials in Huid media,comprising at least one set of shafts and associated flight sectors forconveying said materials in an ascending, stepped, generally spiralpattern, each such set comprising at least two vertically extendingparallel shafts journalled for axial rotation, a multiplicity ofradially extending flight sectors, each having a leading and trailingedge, mounted on each of said shafts and, upon rotation of said shafts,defining annular flight path zones, said flight path zones of each shaftoverlapping and intermeshing with the flight path zones defined by theHight sectors of each other shaft in said set and each flight path zonebeing axially spaced from adjacent flight path zones on the same shaft,each flight path zone being occupied only by the flight sectors of asingle shaft, and a vertically extending smooth-walled housing enclosingsaid shafts and said Hight sectors, said housing conforming closely tothe outer envelope of all of said Hight path zones.

5. Apparatus for moving solid and semi-solid materials in fluid media,comprising at least one set of shafts and associated Hight sectors forconveying said materials in an ascending, stepped, generally spiralpattern, each such set comprising at least two vertically extendingparallel shafts journalled for axial rotation, a multiplicity ofidentical radially extending Hight sectors, each having a leading andtrailing edge, mounted on each of said shafts and, upon rotation of saidshafts, defining a plurality of identical annular Hight path zones, saidHight path zones of each shaft overlapping and intermeshing with theHight path zones defined by the Hight sectors of each other shaft insaid set and each Hight path zone being occupied only by the Hightsectors of a single shaft and being axially spaced from an adjacentHight path zone on the same shaft a distance corresponding to the totalthickness of i. l the overlapped Hight path zones therebetween, and avertically extending smooth-walled housing enclosing said shafts andsaid Hight sectors, said housing conforming closely to the outerenvelope of all of said Hight path zones.

6. Apparatus for moving solid and semi-solid materials in fluid media,comprising at least one set of shafts and associated Hight sectors forconveying said materials in an ascending, stepped, generally spiralpattern, each such set comprising at least two vertically extendingparallel shafts journalled for axial rotation, a multiplicity ofidentical radially extending Hight sectors, each having a leading andtrailing edge, mounted on each of said shafts and, upon rotation of saidshafts, defining a plurality of identical annular Hight path zones, saidHight path zones of each shaft overlapping the Hight path zones definedby the Hight sectors of each other shaft in said set and each Hight pathzone being occupied only by the Hight sectors 0f a single shaft andbeing axially spaced from adjacent Hight path zones on the same shaft adistance corresponding to the total number of shafts in said set, minusone, times the vertical thickness of a Hight path zone, and a verticallyextending smooth-walled housing enclosing said shafts and said Hightsectors, said housing conforming closely to the outer envelope of all ofsaid Hight path zones.

7. Apparatus for moving solid and semi-solid materials in Huid media,comprising at least two vertically extending parallel shafts journalledfor axial rotation, a multiplicity of radially extending Hight sectors,each having a leading and trailing edge, mounted on each of said shaftsand, upon rotation of said shafts, defining annular Hight path zones,said Hight path zones of each shaft overlapping and intermeshing withthe Hight path zones defined by the Hight sectors of at least one othershaft and each Hight path zone being axially spaced from adjacent Hightpath zones on the same shaft, each Hight path zone being occupied onlyby the Hight sectors of a single shaft, said Hight sectors having apitch angle so that the leading edge of a Hight sector is lower than thetrailing edge of said Hight sector by a vertical distance of betweenzero and 12 inches, and a vertically extending smooth-walled housingenclosing said shafts and said Hight sectors, said housing conformingclosely to the outer envelope of all of said Hight path zones.

8. Apparatus for conveying solid and semi-solid materials upwardlythrough Huid media, comprising at least two vertically extendingparallel shafts journalled for axial rotation, a multiplicity ofradially extending Hight sectors, each having a leading and trailingedge, mounted on each of said shafts and, upon rotation of said shafts,de-

Hning annular Hight path zones, said Hight path zones of each shaftoverlapping and intermeshing with the Hight path zones defined by theHight sectors of at least one other shaft and each Hight path zone beingaxially spaced from adjacent Hight path zones on the same shaft, eachHight path zone being occupied only by the Hight sectors of a singleshaft, a vertically extending smooth-walled housing enclosing s'aidshafts and said Hight sectors and conforming closely to the outerenvelope of all of said Hight path zones, a screen through which Huidmedia may be withdrawn from said housing having a vertically extendingportion attached to the lower end of said housing enclosing the lowerHight sectors and conforming closely to the outer envelope of all ofsaid Hight path zones and having a bottom portion underlying thelowermost Hight path zone, means comprising a casing and a pan enclosingand spaced outwardly from said screen, a conduit extending from said panfor withdrawing Huid media from said housing through said screen, inletmeans extending through said casing and said screen for introducingsolids into said housing, Huid inlet means extending through the upperend of said housing and discharge means at the upper end of saidhousing.

9. Apparatus for conveying solid and semi-solid materials upwardlythrough Huid media, comprising at least two vertically extendingparallel shafts journalled for axial rotation, a multiplicity ofradially extending Hight sectors, each having a leading and trailingedge, mounted on each of said shafts and, upon rotation of said shafts,defining annular Hight path zones, Said Hight path zones of each shaftoverlapping and intermeshing with the Hight path zones defined by theHight sectors of each other shaft and each Hight path zone being axiallyspaced from an adjacent Hight path zone on the same shaft, each Hightpath zone being occupied only by the Hight sectors of a single shaft, aplurality of intermediate Hight sectors, radially mounted on each ofsaid shafts and, upon rotation of said shafts, defining intermediateHight path zones located substantially midway between pairs of adjacentaxially spaced Hight path zones, and a vertically extendingsmooth-walled housing enclosing said shafts and said Hight sectors, saidhousing conforming closely to the outer envelope of all of saidoverlapping and intermeshing Hight path zones.

References Cited in the file of this patent UNITED STATES PATENTS2,857,907 Kaether et al. Oct. 28, 1958 2,885,311 Brunicke-Olsen et alMay 5, 1959 2,950,998 Stewart et al. Aug, 30, 1960

1. APPARATUS FOR MOVING SOLID AND SEMI-SOLID MATERIALS IN FLUID MEDIA,COMPRISING AT LEAST TWO VERTICALLY EXTENDING PARALLEL SHAFTS JOURNALLEDFOR AXIAL ROTATION, A MULTIPLICITY OF RADIALLY EXTENDING FLIGHT SECTORS,EACH HAVING A LEADING AND TRAILING EDGE, MOUNTED ON EACH OF SAID SHAFTSAND, UPON ROTATION OF SAID SHAFTS, DEFINING ANNULAR FLIGHT PATH ZONES,SAID FLIGHT PATH ZONES OF EACH SHAFT OVERLAPPING AND INTERMESHING WITHTHE FLIGHT PATH ZONES DEFINED BY THE FLIGHT SECTORS OF AT LEAST ONEOTHER SHAFT AND EACH FLIGHT PATH ZONE BEING AXIALLY SPACED FROM ADJACENTFLIGHT PATH ZONES ON THE SAME SHAFT, EACH FLIGHT PATH ZONE BEINGOCCUPIED ONLY BY THE FLIGHT SECTORS OF A SINGLE SHAFT, AND A VERTICALLYEXTENDING SMOOTH-WALLED HOUSING ENCLOSING SAID SHAFTS AND SAID FLIGHTSECTORS, SAID HOUSING CONFORMING CLOSELY TO THE OUTER ENVELOPE OF ALL OFSAID FLIGHT PATH ZONES.